Semiconductor Ring Lasers Coupled by a Single Waveguide

TL;DR

This paper investigates the behavior of semiconductor ring lasers coupled via a single waveguide, revealing how coupling destabilizes certain lasing states and induces new output states, with implications for optical memory and neural network applications.

Contribution

It provides both experimental and theoretical insights into the destabilization effects and output states of coupled semiconductor ring lasers, a novel analysis for this configuration.

Findings

Coupling destabilizes the in-phase lasing state.

Coupling induces a balanced output state.

Destabilization resembles behavior of optically injected lasers.

Abstract

We experimentally and theoretically study the characteristics of semiconductor ring lasers bidirectionally coupled by a single bus waveguide. This configuration has, e.g., been suggested for use as an optical memory and as an optical neural network motif. The main results are that the coupling can destabilize the state in which both rings lase in the same direction, and it brings to life a state with equal powers at both outputs. These are both undesirable for optical memory operation. Although the coupling between the rings is bidirectional, the destabilization occurs due to behavior similar to an optically injected laser system.